Geological Origins

Can you believe the sedimentary rock of Capricorn Caves started forming under the sea?! About 390 million years ago, corals growing in shallow waters around volcanic islands started building up as limestone on the sea floor. In the tumultuous geological period that followed, this limestone bed was uplifted in a series of crustal plate collisions and volcanic eruptions.

After the limestone emerged from the sea to become land, it was exposed to acidic rain water and underground water flowing through cracks. These waters dissolved the calcite in limestone, hollowing out caves and re-depositing as decorations or speleothems.

Fossils and bone deposits

Marine fossils of the original corals can still be seen in Capricorn Caves. These corals are the rugosa and tabulate types–not the reef-building corals of today. Crinoids (sea lilies) were abundant and stromatoporoids, sponge-like filtering organisms with hard skeletons, built up large mounds of limestone.

We never stop learning from the rocks and deposits in our exciting cave system. In 2005, a team led by Scott Hocknull from Queensland Museum excavated the guano floor in Colosseum Cave. This paleontology dig site “revealed one of the most significant bone deposits to be found in Australia”. Analysis of bones and speleothems is revealing fine-scale change of fauna in the Caves region over the last 400,000 years and contributing to our knowledge of climate change.

Flora and Fauna

The dry rainforest or semi-evergreen vine thicket at Capricorn Caves has survived and adapted to increasing aridity. The rare fern Tectaria devexa, seen in cave entrances, was threatened with extinction in 2006 after decades of drought. A threatened species recovery program has helped stabilise the fragile species, but we continue to closely monitor all known fern sites.

Five bat species roost in Capricorn Caves at different times of the year, but all favour the caves in warm wet weather. Little bent-wing bats Miniopterus australis visit in their thousands, whereas Australia’s largest carnivorous bat, the vulnerable ghost bat Macroderma gigas, is rarely seen.

Human history

Aboriginal people have long known of the caves, and it is part of the Darumbal people’s traditional homeland.

The site’s history in tourism started in the 1880s, when Norwegian John Olsen settled in the area. His sons discovered the caves while looking for their horses and three years later, John opened the caves to tourists. This makes it Queensland’s longest-running tourist attraction.

In 1988, after four generations of Olsen family ownership, Rodney Olsen sold the freehold property to Ken and Ann Augusteyn. Aiming for excellence in conservation, the Augusteyn family developed an environmental management policy for the property and still seek expert input today. The Augusteyns and their passionate team earned Advanced Ecotourism certification in 1997 and have won five Queensland Tourism Awards (most recently in 2014) for raising industry standards.